Water scarcity has been on the international agenda for a few years now (OECD, 2012; UNEP, 2012). Overuse of freshwater resources has already caused environmental degradation in many locations, and causes significant economic and health risks as well. However, the problem can get much worse in the future, with continued population growth and economic development. That’s why researchers like me build computer models: to get a better idea of how water demand and availability may change in the future.